Quote from cnms2:
It may be correct for your trading approach, but the longer time frame price envelopes are proportionally narrower than the shorter time frame ones.
Draw an envelope that barely includes all the price points on a weekly chart, one on a daily chart, one on a 30 minute chart, and one on a 5 minute chart.
You'll notice that the ratio between the envelopes is less than the ratio between time frames. If you increase your time frame 5 folds (daily to weekly), a daily envelope of i.e. $2 will not become $10, but something closer to $4.5.
This suggests that as you go down towards smaller time frames, proportionally there's higher potential of making money.
This also suggests that market characteristics change between time frames, longer time frames being more suited for counter-trend trading, shorter ones for trend trading.
Another aspect to consider is compounding: longer time frame means less trading opportunities, hence making money slower. On the other hand shorter time frame, less absolute price swings, means higher slippage and commissions impact.
I think you are just explaining that Volatilty increases with the square root of time,and it is NOT an linear relationship..Very good point..
I get the strong impression that very few of the posters have compared sytem returns on dailys versus intraday data.I would suggest it is worth ones time to do so,and not look at net return as the sole determing factor.Take a good look at the perspective recovery factors,and yo may gain some interesting insight..
good luck and good trading to all

